13.3.2 Test (CST): Force und Motion Question 7 of 8
Which diagram describes an object moving at a constant speed?
Distance versus Time
300
250
200
O A
Distance (km)
150
100
50
24
Time (h)
Velocity versus Time
o
Velocity (mph)
12
3 4 5 6 7
Time
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2points why do scientists need governmental funding? o a. government politicians ask all the important scientific questions. o b. scientists have to pay taxes to the government on the money they make. o c. the cost of doing scientific research can be very high. o d. the government is controlled by scientists. submit

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

What is the percentage of hydrogen in c2h4